Myocardial blush grade (MBG) is used to assess myocardial perfusion in the infarcted myocardium. The purpose of this study was to determine whether the analysis of myocardial blush grade after resolution of the acute phase of myocardial infarction is useful for assessing myocardial viability. The present study is consisted of 64 patients (55 men, mean age 55 11 years) who had acute myocardial infarction and nonoccluded stenosis (>50%) in an infarct-related artery. All the patients had thrombolysis in myocardial infarction (TIMI)-3 flow in the infarct-related artery on coronary angiograms. Myocardial viability was determined by single-photon emission computed tomography (SPECT) within the same week after coronary angiograms. MBG 0 in 5 (8%) patients, grade 1 in 10 (16%) patients, grade 2 in 23 (36%) patients, and grade 3 in 26 (40%) patients were present. Fifty-four (84%) of 64 patients showed myocardial viability by SPECT. Myocardial viability was demonstrated in 1 1 of 15 patients (74%) with MBG 011 and 43 of 49 patients (88%) with MBG 2/3. There was a weak relation between MBG and myocardial viability by correlation analysis (r = 0.28, p = 0.025). If MBG 0 and 1 are regarded as a sign of nonviable myocardium, and if MBG 2 and 3 are regarded as a sign of viable myocardium, the sensitivity of MBG for the prediction of myocardial viability was 79%, specificity was 40%, positive predictive value was 88%, and negative predictive value was 27%. MBG has a weak correlation with myocardial viability. Although sensitivity is fairly good, specificity is very low. We concluded that the diagnostic value of MBG is limited to detect myocardial viability in the infarcted region.